Enhanced removal of acid orange II from aqueous solution by V and N co-doping TiO2-MWCNTs/γ-Al2O3 composite photocatalyst induced by pulsed discharge plasma

This paper presents a study of V and N co-doping TiO 2 embedding multi-walled carbon nanotubes (MWCNTs) supported on γ -Al 2 O 3 pellet (V/N-TiO 2 -MWCNTs/ γ -Al 2 O 3 ) composite photocatalyst induced by pulsed discharge plasma to enhance the removal of acid orange II (AO7) from aqueous solution. The photocatalytic activity of the V/N-TiO 2 -MWCNTs/ γ -Al 2 O 3 composite to AO7 removal induced by the pulsed discharge plasma was evaluated. The results indicate that the V/N-TiO 2 -MWCNTs/ γ -Al 2 O 3 composite possesses enhanced photocatalytic activity that facilitates the removal of AO7 compared with the TiO 2 -MWCNTs/ γ -Al 2 O 3 and TiO 2 / γ -Al 2 O 3 composites. Almost 100% of AO7 is removed after 10 min under optimal conditions. The V 0.10 /N 0.05 -TiO 2 -MWCNTs/ γ -Al 2 O 3 photocatalyst exhibits the best removal effect for AO7. Analysis of the removal mechanism indicates that the enhancement of the removal of AO7 resulting from V and N co-doping causes TiO 2 lattice distortion and introduces a new impurity energy level, which not only reduces the band gap of TiO 2 but also inhibits the recombination of the pairs. An efficient and easily recycled V/N-MWCNTs-TiO 2 / γ-Al 2 O 3 composite was prepared. Activity of the composite induced by discharge plasma to AO7 removal was evaluated. Synergistic effect of discharge plasma and catalyst effectively improve AO7 removal. The composite demonstrates adequate recycling performance in a discharge plasma system. Possible mechanisms of AO7 removal were analyzed.